Well, Perfect isn't really past time. Perfect is described as an action completed in the present. Aorist is past, but... the nature of the action is kind of sketchy to me right now. Goodwin's book says the aorist is the "simple occurance of an action in past time."

You're going to have to learn not just about tenses but aspect. There are entire books on the subject, but I doubt you need to read entire books on it to understand it. Also, aspect is a new concept so that word isn't going to be mentioned in old grammar books. But anyways, there are other ways to understand aorist and perfect. I mean people have gotten by without knowing about aspect for hundreds of years.

hi eureka, just to add to what 1%homeless already said, the perfect (i think) concentrates more on the current state of the subject following an action, while the aorist just reports the raw "fact" of the action.

an english equivalent of these 2 aspects might be "he is dead" (state) vs "he died" (the fact of him dying).

but this doesn't mean that every time you see the aorist or the perfect, they're used to bring out exactly this aspect of an action. normally the intro to a commentated version of a greek author describes how the author uses particular constructions (and tenses sometimes i think).

Modern linguists describe aspect using the terms 'imperfective', 'perfective', and 'perfect'.

Aspectually, the aorist is 'perfective'. Perfective use means that the verb makes no explicit reference to the internal temporal constitution of a state. That is, it reveals nothing about the internal order and phases of a situation. This doesn't mean that the situation lacks such features. Rather the perfective verb simply doesn't refer to them.

(A relatively clear contrast in Greek is that between the indicative mood imperfect and aorist. Both refer to past time, but former is imperfective, the latter perfective.)

Aspectually, the perfect typically relates a state to a preceding situation. Chad gave a relevant example using 'to die'. Or consider the sentences:

I lost my book. - (non-perfect)
I have lost my book - (perfect)

The perfect version more strongly suggests that the book is still lost; the non-perfect version does not. This is the so-called 'perfect of result' - the most familiar use of the perfect. Many linguists doubt if the perfect is an aspect at all.

I hope this helps. Aspect is subtle. I struggle with it every time it comes up on Textkit. Please see Bernard Comrie's "Aspect" in the Cambridge Linguistics series, whence most of this rap.

So does that mean that, in Greek, words that pinpoint the time of the verb's action (i.e. yesterday, earlier, etc) are not used in sentences that have a verb of the perfect tense?
The same way we wouldn't say "I have fed the cat yesterday." *

*Except where the time positioning word refurs the present (i.e. today, this year, etc.)

Eureka wrote:[So does that mean that, in Greek, words that pinpoint the time of the verb's action (i.e. yesterday, earlier, etc) are not used in sentences that have a verb of the perfect tense? The same way we wouldn't say "I have fed the cat yesterday." *

I'd think time adverbs would match the tense of the perfect form. So, words that make sense with the present tense are probably fine with the present perfect ("I shut now," vs. "I have shut the door now") , and those with the past would go with the past perfect ("I had shut the door on the Ides of March."), or the (rarely used) future perfect, ("I will have shut the door tomorrow").

But I'll have to go digging into some Greek texts to verify all of this. However, since there are a number of perfects used commonly to express things we'd use the present for ("to know" [face=spionic]oi)=da[/face] comes to mind), I suspect what I said above is correct for Greek and English both.

You are right to think that, for verbs in the perfect indicative, it is assumed that the speaker is in the present time referring to an action that is completed. To express the idea that at some point in the past the action was completed (as in your example sentence), you would employ - as in English - the pluperfect tense:
I had fed the cat yesterday.

Notice, however, that the above applies to the indicative mood. There are perfect tense verbs in all five moods, and in some moods the verb does not carry information about time!
For example, you could have a perfect infinitive (conveying the idea: to have done something) appearing with a time-word referring to the past - e.g.
To have done this last year would have been impossible.

There are two types of verbs, stative (states... often rendered into english by "I am" e.g. I am afraid... I am in the state of knowing (I know!) etc) and eventive, which are actions with a start and a finish.

Though stative verbs ARE NOT A TENSE (a state has no concept of time: I like Greek = I am accustomed to like Greek; I will like greek, i probably used to like it as well). they do give us the greek perfect forms. What defines the perfect tense is not so much relation to present time, but rather a STATE.

Eventive verbs come in two forms: punctual - actions that happen in an instant, e.g. i arrive, I snap, and durative - actions which take time, e.g. I learn, I walk. In PIE these occured in two forms: the present (strictly "non-past"). The past for punctual verbs is the strong aorist; for durative verbs the imperfect (hence the fact that strong aorists and imperfects take the same endings)

The other kind of aorist - sigmatic aorist - is a way of viewing a durative verb as a process.

I'm sure this is far more complicated than Eureka wanted - sorry - but it's a very interesting topic.

"New Comparative Grammar of Latin and Greek" is a good source for all this

Thank you Thucydides. This looks like a really good book. I thought I would have to wait for a long time for something newer than Carl Darling Buck's Comparative Grammar of Greek and Latin to come out.